Property, Plant And Equipment (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 1,811	$ 1,675	$ 1,746
Interest capitalized	74	57	48
Rental expense for leased properties	276	270	269
Minimum rental payments under capital leases, total	152
Minimum rental payments under operating leases with initial or remaining terms of one year or more, total	1,386
Sublease payments under operating lease	18
Accounts payable	9,394	8,406
Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Depreciation expense	1,248	1,119	1,096
Accounts payable	$ 234	$ 200